Pitting machines are known in which the drupes are entrained by a transporter in the form of an endless chain whose links are constituted by hingedly interconnected perforated conveyor plates, the chain being advanced with a stepped motion past a pitting station disposed along its horizontal run. As shown for instance in U.S. Pat. No. 667,423, each plate is provided with an upwardly concave seat of ogival shape designed to receive a drupe. When the seat passes through the pitting station, a pusher or punch descends to dislodge the pit from the pulp of the drupe, specifically an olive to be subsequently stuffed; the pit is being thrust by the pusher through a narrower orifice in the plate. The drupe is subsequently dislodged by gravity from its seat, through the open end thereof, in an inverted position. Especially with prunes and similar fruits of the type referred to above, however, practice has shown that a small fleshy cap underlying its pit tends to remain attached to the pulp and to adhere to the pit-clearing orifice in a manner impeding the subsequent ejection of the drupe. Even if the cap is detached from the body of the fruit, its fragments may contaminate the seat so as to interfere with the further operations. This problem is less severe with softer fruits, such as cherries or apricots, but is aggravated with prunes, dates or the like by the fact that these fruits are generally prewetted with water in order to separate them from a heap for individual passage through a hopper at a loading station preceding the pitting station. In fact, the juice of these fruits when diluted with water has the character of a fairly strong adhesive.